The invention relates to a process and a device for the exchange of full thread packages for thread bobbins (or tubes) on spinning machines with spindles, and more particularly to processes and devices for obviating the necessity for removing excess thread coilings which normally occur during doffing and donning operations in yarn or thread spinning machines, particularly in connection with cap spinning machines.
Before the doffing of full thread packages, also called cops, underwinding crowns frequently occur in spinning machines. Such thread windings or thread coilings located underneath the crown must eventually be removed. A typical method for removing such underwound coils is to rub them off by means of a bar with abrasive paper or the like which is swiveled against the underwinding part during a subsequent spinning process. A consequence of such a process is that fly is generated permeating the air in the spinning room which is onerous for spinning machine operating personnel and injurious to health. Another typical means of removing such underwindings involves the use of a robot moving along the machine for removing superfluous thread windings through such means as scratching, cutting and suction. Typically such robots are dedicated to this one function, so that considerable additional expense is incurred for coordination with other robots performing other needed functions such as piecing.
The presence of a spinning cap results in particular problems when doffing cap spinning machines. An underwind crown would not be practical with such machines. One doffing method makes use of an inserted or plugged-in attachment in the upper end of the tube, on which an overwinding is wound. The attachment is transferred from a full package to a new (empty) tube either manually or mechanically. One disadvantage is having to clean the attachment. As the attachment must remain on the tube during spinning, precautions must be taken to ensure a reliable but detachable connection between the tube and the attachment. The possibility exists nevertheless, because sufficiently reliable tube connections are not available, that the attachment may get out of control at normal rotational speeds, typically up to as much as 20,000 rpm and above, presenting a potential danger for operating personnel and potential damage to machine parts.
It is, therefore, an object of the present invention to provide a method and a device for doffing and exchanging full thread packages, particularly in connection with cap spinning machines, which overcomes the disadvantages previously mentioned particularly those involving danger to man or machine and difficulties in removing thread residues.